P1398

Code

CHEVROLET P — Powertrain

Wheel Speed Sensor 2, G-Sensor Circuit High Voltage

Brand: CHEVROLET

Type: P — Powertrain

Views: UK: 24 EN: 46 RU: 41

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Page language: EN

Causes

Short to battery positive on the sensor wiring
Damaged or corroded sensor connector or terminals
Faulty wheel speed (or G) sensor
Open or high resistance in ground/reference circuit
Intermittent wiring damage (pinched, chafed)
Faulty ABS/BCM/PCM input or module internal fault

Symptoms

ABS light and/or traction/stability control warning lamp illuminated
Possible loss of ABS/traction/stability functionality
Illogical or intermittent wheel speed readings on scan tool
Cruise control disabled or speedometer irregular (depending on system)
Brake system warnings during diagnostic events

What to check

Scan for stored codes and related ABS/traction/stability codes
Visually inspect sensor 2 harness, connector, and wheel area for damage/corrosion
Check for aftermarket devices or recent repairs near wiring harness
Backprobe connector with ignition ON and measure signal and reference voltages
Compare live data from the sensor to other wheel sensors using a scan tool
Perform wiggle test of harness while monitoring signal for intermittent faults

Signal parameters

Hall-type wheel speed sensors: signal typically a square/pulsed waveform referenced to 0–5 V (rest often near ~0.5–2.5 V depending on design) — should not exceed battery voltage or rail limits
VR (magnetic) sensors: AC sine waveform with amplitude proportional to wheel speed (millivolts to volts); not a steady high DC voltage
G/gyro/accelerometer type sensors: usually supply/reference ~2.5 V nominal with small ± voltage swing — consult vehicle service manual for exact resting and swing voltages
Refer to factory service data for exact voltages, waveforms and pin assignments for Wheel Speed Sensor 2

Diagnostic algorithm

Record freeze frame/live data and note related ABS/traction codes. Do not clear codes yet.
Visually inspect the wheel sensor, tone ring, sensor mounting and harness at the wheel for damage, contamination or metal debris.
Disconnect the sensor 2 connector. Inspect terminals for corrosion, bent pins, or pushed-out pins. Repair/clean or replace as needed.
With connector disconnected, turn ignition ON (engine OFF). Measure reference and supply voltages at the harness side (not the sensor). Look for an unexpected steady high voltage (close to battery) on the signal or reference circuit.
If high voltage present at harness, trace wiring toward the module looking for a short to battery (inspect splice points, connectors, body harness routing).
If harness voltages are normal, reconnect sensor and backprobe signal/wiring while rotating wheel or performing a road/roller test to observe waveform with an oscilloscope or scan tool.
If waveform is abnormal or shows high DC, swap with a known-good sensor (same type/location if possible) or install a replacement sensor and retest.
If new sensor and harness checks OK but code returns, test continuity and resistance between sensor connector and control module input. Repair any opens/high resistance.
If wiring and sensor check good, consider module input fault—verify with module bench data or consult factory diagnostics before module replacement.
Clear codes and perform a controlled road test while monitoring live data to confirm repair.

Likely causes

Corroded/contaminated sensor connector allowing voltage leak
Short to battery voltage on the sensor signal or reference wire
Failed wheel speed sensor (Hall type) internally outputting high voltage
Poor ground or open return for the sensor reference
Module input fault (less common) after wiring and sensor checks

Fault status

⚠️ Status

P1398 - Wheel Speed Sensor 2 / G‑Sensor Circuit High Voltage

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2 hours

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